The invention relates to a microscope for the noncontact wide-angle viewing of an eye with the help of an optic which is provided between the lens of the microscope and the eye and which lies in the optic axis of the lens, and can be moved in the direction of the optic axis, during surgery on the eye, in particular, the microscope can be moved by means of a linear gear that is arranged in a device which consists of a mounting mountable on the microscope and a holding arm for the optic that can be moved on the mounting, wherein the linear gear is arranged between the mounting and the holding arm.
A wide-angle viewing of the eye can be done in a simple manner by a contact lens that is directly placed on the eye.
An additional optic between the eye and the lens, which optic cannot be moved with reference to the lens, can only be used in a limited manner because the surgeon must often change the image plane during surgery. It is therefore important that the optic additionally mounted on the microscope can be refocused.
A microscope of this type is already known, for example, from the U.S. Pat. No. 5 793 524. A linear gear is thereby provided to help move an optic, which is provided on the holding arm, in the direction of an optic axis of the microscope relative to its lens. The holding arm includes a first rotatable gear element thereon which couples to a second linear gear element that is provided in a mounting connected to the microscope and is nonrotatable on the mounting. The linear gear can thereby consist, for example, of a threaded spindle and a spindle nut that is longitudinally movable through rotation on the threaded spindle, or of a rack and a pinion movable along the rack through rotation. Accordingly, the spindle nut or the rack each form the first gear element provided on the holding arm and the threaded spindle or the rack each form the second gear element provided on the mounting. A handle is connected to the first gear element to help rotate the first gear element so that it is indeed possible for the surgeon to also adjust the focal distance of the microscope during surgery.
Of course it is not advantageous when the surgeon, who must in most instances guide the surgical instruments with both hands during surgery on the eye and must also operate the handle to refocus. Thus, the surgeon must either interrupt the surgery to refocus or must have the refocusing done with the help of an assistant who can carry out this task only via instructions from the surgeon who is looking through the microscope. Both of these options are complicated and time-consuming.
A microscope according to the present invention does not need any auxiliary means directly provided on the eye and yet realizes a focal distance which guarantees a sufficient image field during the surgery. The surgeon has thereby available the area between the optic and the eye in order to be able to guide the surgical instruments unhindered.
One goal of the present invention is to replace the handle with an electromotive drive, the switching device of which can also be operated by the surgeon during surgery without the need to put down the surgical instruments and thus without the need to interrupt the surgery.
The basic purpose of the instant invention is to provide a microscope of the type identified in detail above in such a manner that the optic for wide-angle viewing can be refocused by the surgeon during surgery on the eye without having to interrupt the surgery, wherein the arrangement is yet such that damages through autoclaving during the necessary sterilization of the device can be avoided.
The purpose is attained according to the invention by the linear gear being operable by an electromotive drive, the output of which is connected to the linear gear through a flexible drive shaft. In this manner, it is possible to remove the electromotive drive from the area in which all other parts must be sterilized prior to each surgery. The drive shaft, unlike the electromotive drive, can be sterilized without being damaged so that the microscope according to the invention can indeed be easily switched by the surgeon during surgery without the need to interrupt such surgery, and without influencing the life span of the microscope through repeated sterilization of its parts which are exposed to the surgical area.
It is particularly advantageous, for example, when the electromotive drive is provided on the microscope in the area of the eyepiece housing. The drive can be relatively small because the drive power needed for the linear gear is very low. As a result of its correspondingly small volume, its arrangement directly on the microscope hardly interferes with its compact design and, on the other hand, it is assured that the needed flexible drive shaft can be relatively short and can be arranged so that it does not interfere during use.
When the mounting is fastened on the lens housing of the microscope, it is thereby advantageous, so that again a flexible drive shaft that is as short as possible can be realized.
In a preferred embodiment of the microscope according to the invention, the linear gear is designed as a spindle drive with a threaded spindle which is supported parallel to the optic axis and is spaced from same. The linear gear is rotatably supported on the mounting, whereby an adjusting wheel connected to the holding arm is guided longitudinally movably on the threaded spindle, and the threaded spindle can be driven by the drive shaft. The spindle nut is hereby, as a rule, fixed against rotation and is locked accordingly. The arrangement, however, can also be such that the rotary locking of the spindle nut can be disengaged so that the spindle nut can in turn be used for the manual drive of the linear gear; the flexible drive shaft must thereby not necessarily be locked fixed against rotation because it can have a sufficient automatic locking.
The entire device, which is needed on the microscope for the additional optic, the so-called BIOM-System, and which is to be newly sterilized prior to each surgery, can without any difficulties be completely separated from the microscope when the drive shaft, in particular in the area in which the electromotive drive remains on the microscope, is easily releasable.
It is particularly advantageous when the drive shaft is divided into two parts, whereby a first shaft piece is fastened to the output of the electromotive drive so that it cannot easily be removed and a second shaft piece is drivingly connected to the threaded spindle that can be easily uncoupled from the first shaft piece by means of a coupling. The coupling can be designed to be easily releasable without any difficulties so that the shaft pieces can be mounted both on the electromotive drive and also on the mounting or on the threaded spindle there supported so that they cannot be easily separated and accordingly so that the relatively fixed mechanical connections can prevent operating errors. Again, considering the sterilization of the device, it is best that the coupling of the shaft pieces is such that the coupling is always above the microscope lens. The shaft piece that is connected to the mounting is completely sterilized during autoclaving so that only the part of the drive shaft that is removed far from the area between the lens and the eye remains nonsterile.
It is convenient when setting up the microscope that a switching device for the electromotive drive is arranged in such a manner that it can be switched simultaneously with the operation of other handles of the microscope.
During surgery on the eye, it is possible for the surgeon to refocus the optic by means of a foot switch that can adjust the electromotive drive. The surgeon can hereby continue surgery with both hands without having to interrupt the procedure or use an assistant. This significantly increases the safety of the surgery while the duration of the surgery is not unnecessarily extended due to needed manipulations of the microscope. As an alternative, a hand switch which is operated by an assistant is also possible.
The optic can house a reversing prism so that the field of vision of the microscope is reflected nonreversed in the eyepiece.
Although the invention significantly improves the microscope for the intended purpose without excessive expense and in an apparatus-technically simple manner so that the function of the microscope is improved and its servicing is simplified, while all necessary parts of the microscope can be continuously and regularly sterilized.